AGGREGATE EXTRACTION AS THE TRIGGER FOR A NEW LANDSCAPE ON THE BANKS OF THE MAIPO RIVER
Extracting sand and gravel (aggregate) in Chile is concentrated in the country’s principal rivers, giving rise to multiple ecological conflicts and generating an important impact. Given that the product obtained in this process is the raw material for building construction, it is impossible to consider stopping this activity of extraction. In this scenario and to transform the problem into an opportunity, a collaborative solution is proposed which connects the productive, ecological, and social components in such a way that each can benefit and no one is denied access.
The hydrographic basin of the Maipo River has one of the main watercourses of Chile, crossing the whole of the Metropolitan Region as well as part of Regions V and VI. This water resource is valuable because it supports wide ecological diversity as the habitat for local flora and fauna. This wealth makes it part of the Priority Sites for Conservation Diversity (1). Furthermore, it supports human settlements and as such there are swaths of land with productive purposes within the river basin. Finally, it plays a role in a growing potential for tourism and leisure enjoyment within the landscape.
(1) The definition of Priority Sites for the Metropolitan Region was made during the years 2002 and 2003, with 23 sites defined. This process began with the creation of an Operational Committee, coordinated by CONAMA RMS, including the Regional Secretary of Agriculture, and members from the Regional Directorates of the Agricultural and Livestock Service, the National Forestry Corporation and the National Fisheries Service. The objective of the Priority Sites is to protect ecosystems, species, and genes to ensure the long-term survival of representative biodiversity in the area.
The Maipo River has been productively used for agriculture, livestock, mining and currently for hydroelectric generation and aggregate extraction. This latter activity of extraction has grown over the last years to include 37 points along the river. Specifically, the upper sub-basin of the Maipo River, commonly called the Cajón del Maipo due to its topographic constriction and abrupt change of height, is one of the areas with the greatest diversity of ecosystems on the river, but also with the highest concentration of aggregate extraction areas. Its topography and proximity to the mountains make it the area with the highest flow of the entire basin, which is also why it concentrates a large amount of sediment – the aggregate extraction material sought after by the construction industry. Thus, 40% of the Maipo River’s extraction industry occurs on just one quarter of its total length, causing a perceptible change in the landscape. On the sandy banks (2), where the aggregate extraction is carried out, the riparian vegetation of the river’s edge is constantly being destroyed, changing existing ecosystems, degrading them and eliminating them. In addition, a topographic transformation is occurring, as taking away or removing soils create a new landscape and open new views, terraced sections and mountains.
(2) The banks correspond to a process of natural extraction of aggregate (sand and gravel). The flow of water is directed through channels to the bank where the sediment that brings the water is mechanically extracted. The flow of water is returned to the center of the riverbed. The aggregate is then classified to later sell the raw material.
Currently, extraction is not regulated. The consequences of this lack of regulation are excessively large areas without organic systems and areas that are deeply altered by the level of removal. In the case of aggregate extraction from the river bed, the activity is not only invasive in terms of dimension and volume, but also in terms of its time scale. As the sediments are renewed with the force of water and increased flows, the productive activity is permanent and perpetual. As a result, the overexploitation of the Maipo River has decreased the level of the riverbed and the river’s depth. As there are no limits on production, the extraction plants expand even to the populated areas, which signifies reduced public access to the river. There is also no ecological awareness on the part of the aggregate industries, implementing single-function infrastructure without ecological or social considerations.
Given the existing conditions and laws for the management of extraction activities in Chile, mitigation or regulation strategies have been proposed by companies only posterior to the process of extraction. As it stands, remediation activities begin once the extraction activities have been completed. In this scenario, it is worth asking: Instead of stopping the productive process for the protection of the basin, why not participate in the other processes and dynamics of the territory to promote the resilience of its local ecology?
A possible answer is to understand the transformations and impacts generated by productive activities as new landscape possibilities and therefore new encounters between natural systems and culture. Aggregate extraction in its current form, if associated with a landscape architecture project could trigger new programs through the coexistence of various types of production and compatible new recreational and educational uses.
The thesis project, “Redefining a Productive Landscape: The harvest of aggregates as a trigger for a new hybrid landscape on the banks of the Maipo River, ” promotes the recognition, activation and reclamation of the productive landscape by addressing three key aspects: the productive, the ecological and the social. This involves rethinking and reorganizing the spatial configuration of the productive landscape through the redefinition of the systems, favoring the ecological recuperation of the riverbed and its vegetation, recognizing and intensifying the new ecologies generated in that place, and finally creating multiple programs compatible with the productive landscape in the form of a park. Including the human element in this system is proposed as fundamental, as much for its protection and maintenance, as for its activation of activities related to tourism, leisure, and recreation. Although the proposed strategies are aimed at taking care of the ecologies, the intention is not to return the site to its original state, but rather it is hoped a hybridization can be achieved between the anthropic landscapes, both leisure and productive, and the ecological environment.
In short, the proposal is to connect the productive, ecological and social in a multifunctional infrastructure, to build extractive landscapes that dialog with the culture, are active in terms of public use and careful with the physical environment, resulting in sites that are positive not only in economic terms. In this way, under the contemporary disciplinary view of landscape architecture, it is possible to think about the integration of processes and systems as a solution to the eternal conflicts associated with large-scale production in the landscape.
Montserrat Castro Urrutia. Architect (2005) and holds a Master’s degree in Landscape Architecture (2011) from the Pontifical Catholic University of Chile 2017. She is currently an architect at Teodoro Fernández Architects.
(3) Supply for construction in the Metropolitan Region © Montserrat Castro U. for LOFscapes.
(4) Infographic of the productive process of the extraction of aggregates © Montserrat Castro U. for LOFscapes.
(5) Aggregate extraction areas in the Cajón del Maipo © Montserrat Castro U. for LOFscapes.
(6) Analytical catalog of extraction zones © Montserrat Castro U. for LOFscapes.
(7)Existing ecologies in Cajón del Maipo affected by production © Montserrat Castro U. for LOFscapes.
(8) Maipo River at different times of the year, sediment variation © Montserrat Castro U. for LOFscapes.
(9) Study section between Las Vertientes and La Obra © Montserrat Castro U. for LOFscapes.
(10) Study Site. Aggregate extraction zone © Montserrat Castro U. for LOFscapes.
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